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Report
Water Safety
Conference 2010
Richard Walker
Tips for Implementing Water Safety Plans
Water Corporation- Water Supply Profile
Main supplier of drinking water in Western
Australia (WA)
2 million customers spread over 2 million km2
(~10 times the size of the United Kingdom)
245 water distribution schemes in urban, rural
and remote communities
Raw water originates from a wide variety of
sources
Surface water
Groundwater
Sea water
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Water Safety Plans (WSPs) – A Short History
2004
•Latest version of Australian Drinking Water Guidelines
•Featured “Framework for Managing Drinking Water Quality”
•Framework comprises 11 Elements
•Water Corporation commenced preparation of WSPs
•Vehicle to ensure meet the requirements of
Element 2 – Assessment of drinking water supply system
Element 3 – Preventive measures for drinking water quality
management
Element 4 – Operational procedures & process controls
2010
•Completed 160/250 WSPs
•Many have been revised several times
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Tips and Lessons
•We want
-Quality plans and
-Quality implementation
•Highly successful
-multiple revisions
-under pressure from operators to complete all WSPs
-Spontaneous acclaim from operations
•Lessons learnt
-WSP preparation and development
-systems to support WSP implementation
-senior management support & corporate governance
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Tips for Water Safety Plan Development
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Prioritisation (How do I start?)
Pathogens
Chemicals
Naegleria
WSP
Disinfection By
Products
Pesticides
Aesthetics
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Prioritisation (How do I start?) cont’d
Pathogen
s
Chemical
s
Naegleri
a
WSP
Disinfection
By Products
Pesticides
Aesthetics
Which hazards do you want WSPs to help you manage?
The more you tackle
-The longer it takes
-The bigger the plan
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Initial Water Corporation focus for WSPs
Pathogens
Chemicals
Naegleri
a
Nitrate
WSP
Disinfection By
Products
Pesticides
Compliance
Aesthetics
Judgement call based on
Understanding of water quality principles
Knowledge of systems and performance
Experience, especially attitudes of Health Department, Executive
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
WSP Teamwork
Team members are
•Dedicated WSP planners (head office) plus
•Actual operators of the scheme plus
•Regional co-ordinator
Asset plans are often inaccurate/incomplete
Schemes cannot be operated as they were designed
An accurate schematic is essential for the WSP
Only the operator knows the TRUTH
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
WSP Teamwork
Planners must
•Meet the operator on site (up to 4000km trip)
•Plan well for that meeting
•Draft schematic
•Review of monitoring data
•Draft hazard analysis
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Setting the water quality specification
Free Chlorine Residual mg/L
6
5
chlorinator set
point
5.0
Free Chlorine Residual Profile
low er
higher
target
4
11 Mile SP
3
3.0
7 Mile SP
2
2.2
1.5
1.2
1
6 Mile SP
Delamere St
2.0
0.5
1.5
1.5
1.0
1.0
0.4
0.5
Port SP
1.5
0.8
0.3
0
22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Chainage Distance from Port to Chlorinator (km )
Fundamental questions
-What must I have?
-What can I accept?
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Pragmatic Approach
Critical control points are non negotiable
Eg. Chlorinator set point must give Ct >15 for first customer for effective
distribution
Process Control Points need to be practical
Eg. Chlorine residual at end of distribution should be >0.2mg/L to
prevent regrowth, protection for backflow
But if this is not possible all of the time
Eg. Asset configuration, customer complaints, DBPs
Then you need to decide if <0.2 mg/L is OK?
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
What are you asking of an Operator?
Every out of spec monitoring result is a call for action.
If the operator can’t correct by operational change then
Use the action plan to highlight need for asset changes to allow
Corporate Standards to be achieved
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
How frequently do I monitor?
CCPs – continuously
PCP - ? Utility to decide
Practices are likely to vary widely from site to site
Opportunity to standardise
Water Corporation applied
– risk principles
- input from Operators with
accountability for WQ outcomes
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
How frequently do I monitor?
System characteristics
Frequency of field Cl checks
Chlorinator to Corporate Standard Weekly
with SCADA
No SCADA, low risk source, supply Twice/week
into tank
No SCADA, high risk source,
supply into tank
3 times/week
No SCADA, supply direct to
customers (no tank)
Every day
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
How can WSPs be made useful for Operators?
•The WSP is typically 10 – 30 pages
•Too long for an operator
•Water Corporation developed a “one page process control plan”
•What an operator needs to do to deliver acceptable water quality
Process control plan contains
•Schematic
•Operating strategy
•Process control table
-Specification
-Monitoring plan
-Response to out of spec conditions
•Sign off by responsible managers
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
High Level Reticulation
(Approximately 55 services)
SP Chittering L361 Robin Gr
Main Storage Tank
Cap 2.5 ML
TWL 239.77 m AHD
Town Reticulation
Elevated Tank
Cap 0.1ML
TWL 255.50 m AHD
SP Bindoon 11 Bottlebrush Pl
SP L351 Forrest Hill Pde
Bindoon-Chittering Borefield
Supply Main
Confined Aquifer 3.5 km west of the town
Aquifer recharge by leakage from leederville aquifer underneath
Bores are 162-166 m deep
Minimal risk of contamination
150 AC-D
3.9 km from clearwater
tank to storage complex
Volume of water ~ 76 kL
Scheme Operation
Bindoon-Chittering receives water from the borefield located 4 km west of
the town. The borefield has two bores Bore CC1 and Bore CC2. Water
from the bore is oxidised with chlorine and filtered for iron removal.
Disinfected water is injected with soda ash for pH correction. Treated
water is stored in a 90 kL onsite clearwater tank. Water then pumped to
the storage complex where it is stored in the 2.5 ML storage tank before
being distributed in the town. Approximately 55 high level services are fed
from a 100 kL elevated tank.
Bore CC1 is predominantly used for the water production due high iron
content observed in the Bore CC2, which is used as a standby bore.
SP Chittering
Borefield Treated
Water
Pre-Tank NaOH
Chlorine Analyser
Pressure Filter
Disinfection/Oxidation (Set
Dose Rate 8.7 mg/L)
Post-Tank Chlorine
Analyser
SP Chittering
Borefield Raw
Source
Clearwater Tank Cap
90kL
TWL 159.60 m AHD
Backwash Sump
·
·
Water Quality Issues (Distribution)
High Iron (12% of the samples were above the aesthetic guideline limit)
High TFSS (86% of the samples were above 80% of the aesthetic guideline limit)
Bore
CC1
Bore
CC2
Bore CC1
Bore CC2
High Iron up to 7.5 mg/L
High Manganese up to 0.11 mg/L
High Turbidity upt o 31 NTU
High Iron up to 13 mg/L
High Manganese up to 0.2 mg/L
High Turbidity up to 130 NTU
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
·Maintaining chlorine residuals throughout the storages (> 0.5mg/L) and reticulation (> 0.3mg/L)
Process Control Table
Process Control Table
Location
Measurement
Frequency
Data
Storage
Critical Limits
Corrective Actions
RAW WATER
Turbidity
4 Weekly
>85 NTU
Action by Drinking Water Quality
Coordinator
Follow Managing and Responding to
DWQ Incidents – Raw Water Turbidity
> 0 MPN/100mL
Action by Drinking Water Quality
Coordinator
Follow Managing and Responding to
DWQ Incidents – Raw Water E. coli
ODSS
SP Chittering Borefield Raw
Source W4000524
4 Weekly
ODSS
POST DISINFECTION
Critical Control Point
Pre-Tank Chlorine
Analyser
(W0040633_Cl2_Residual_
Analyser_Inlet_instant)
Process Control Point
Post-tank chlorine
analyser
SP Chittering Borefield
Treated Water W4000525
Free chlorine
Free chlorine
PI
Low
Target
High
0.40 mg/L
0.80 mg/L
1.20 mg/L
·Automatic shut off of transfer pumps on low
alarm
·Check analyser vs manual reading
·Check dosing system
Continuously
PI
Low
Target
High
0.35 mg/L
0.75 mg/L
1.15 mg/L
·Check analyser vs manual reading
·Check inlet analyser and dosing system
·Check clearwater tank residual and scour if
necessary
Target
< 0.2 mg/L
4 Weekly
ODSS
Target
6.5 -8.5
Low
Target
High
0.30 mg/L
0.70 mg/L
1.00 mg/L
Continuously
Iron
pH
·Check the treatment effectiveness.
·Notify the Operation Manager.
RETICULATION
SP Chittering L351 Forest
Hills Pde W0040628
Free chlorine
SP Bindoon Bottlebrush Pl
W0040595
Free chlorine
Weekly
ODSS
Low
Target
High
0.20 mg/L
0.40 mg/L
0.80 mg/L
SP Chittering L 361 Robin
Gr W4007179
Free Chlorine
Weekly
ODSS
Low
Target
High
0.30 mg/L
0.70 mg/L
1.00 mg/L
Weekly
ODSS
Contact Supervisor to discuss actions
Actions could include:
oCheck chlorinator
oCheck tank residual
oDose tank
oScour reticulation
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Operating Strategy
The operating strategy for Bindoon-Chittering water supply involves:
•Treatment for iron removal and pH correction is continuous and effective at all times (treated water outlet iron < 0.2 mg/L and pH
between 6.5 and 8.5).
•Ensuring continuous and effective disinfection (Ct > 15)
•Maintaining chlorine residuals throughout the storages (> 0.5mg/L) and reticulation (> 0.3mg/L)
Production (kL/day)
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
990
762
829
333
843
328
304
289
219
443
472
583
Note: Data from July 2003 to June 2007 for WRC Chittering Licence
Action Plan
Maintenance Improvements
Functional
Location #
Recommended Improvement
Who
Priority
Calibration
Ensure maintenance plans are in place to guarantee
calibration of all instrumentation is carried out on a frequency
as per the manufacturers recommendation
MWR
High
Auto shut-off
Check auto shut off functionality as per TAM standards
MWR
High
Tank cleaning
Ensure tanks are cleaned as per TAM standards
MWR
High
Area of Improvement
SAP or Work Order #
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Endorsement
This process control table is endorsed for implementation.
•The Midwest Region agrees to implement the operating strategy.
•The Drinking Water Quality Branch agrees to provide corporate systems, processes and advice to assist the Midwest Region
with implementation.
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Tips for Systems to Support Water Safety Plan
Implementation
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Target ranges – how can I remember them all?
•Sample point stickers with residual targets
•Focusing on Chlorine residuals
•Fast response
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Personal Data Acquisition
Acceptable range is preprogrammed
Prompt to recheck if out of spec
Prompt for remedial action if out of spec confirmed
On line up date
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Email notification system – Out of spec
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Email notification system – Sample overdue
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Tips for Senior Management Support
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Senior Management Support
How to move Corporate focus from
E coli in the reticulation to
Operational Performance
•Source Protection
•Filtration
•Disinfection
•Chlorine residuals
?
Make it easier for Managers to manage ………
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Governance Report
•
The “Governance Report” provides an overview of key Drinking Water Quality
management information in one report (Catchment to Tap)
•
Introduces a common and standard reporting approach on water quality
throughout the state, which establishes due diligence and credibility
•
It shows a summary of compliance and operational reports with drill down
capabilities for further detail
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Governance Report
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Water Safety Plan Performance Review & Reporting
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Water Safety Plan Performance Review & Reporting
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Water Safety Plan Performance Review & Reporting
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Corporate Profile
•Corporate Water Quality Committee
•Leadership/governance role eg.
•WSP production target (30 pa)
•Operational monitoring target (95%)
•Critical limit performance (100%)
•Feedback
•Negative (please explain)
•Positive (eg. 100% chlorine meters calibrated)
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Conclusion
Successful WSP planning is a team effort
Central Branch provide
-Vision
-Understanding of WQ management principles
-Pragmatic decision for local circumstances
Operators provide
-Asset information and condition
-Operating information
-Monitoring service
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Conclusion cont’d
Central Branch provide
•Systems to help operators to implement SWPs
•Management information
Senior Management
•Review performance
•Determine targets/expectations
•Provide positive feedback
Water Safety Conference
November 2-4 2010, Kuching, Malaysia
Conclusion cont’d
Payback
•Common focus for Corporation
•Clear requirements for Operators
•Reduced incidents
•Higher confidence
Water Safety Conference
November 2-4 2010, Kuching, Malaysia

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